| 摘要 |
PURPOSE:To provide an annular permanent magnet with higher mass productivity in an automated line by carrying out molding by limiting a punch press surface configuration of a molding device in which a filter is placed, and partially polishing a resulting sintered structure of a different shape, and further removing an internal periphery burrs on the basis of time surface configuration of the filter. CONSTITUTION:There is employed a slurry in which powder of a permanent magnet material is dispersed in order to obtain an annular permanent magnet 1. The slurry is molded in a magnetic field in a wet atmosphere and is sintered into a sintered structure. The sintered structure 10 as a molded structure is of a cylindrical shape with its internal peripheral part more protruded than its external peripheral part. Upon molding, on one filter side end surface 11 in contact with a filter uneven configuration of the filter is transferred, and hence burrs 17 are formed on the internal and external peripheries of the filter side end surface 11. The internal periphery of the filter side end surface 11 of the sintered structure 10 is polished to remove the internal periphery burrs. Thus, the internal periphery burrs are removed with excellent mass-productivity in an automated line. |
